Method for the treatment of acne using pharmaceutical compositions comprising 0.3% by weight of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid

ABSTRACT

Dermatological disorders having an inflammatory or proliferative component, notably common acne, are treated with topically applicable pharmaceutical compositions containing about 0.3% by weight of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid (adapalene) or salt thereof, formulated into pharmaceutically acceptable media therefor, advantageously formulated into topically applicable gels, preferably aqueous gels, creams, lotions or solutions.

CROSS-REFERENCE TO EARLIER APPLICATIONS

This application is a continuation of U.S. application Ser. No. 14/524,602, filed Oct. 27, 2014, now allowed, which is a continuation of U.S. application Ser. No. 12/957,882, filed Dec. 1, 2010, now U.S. Pat. No. 8,921,423, which is a continuation of U.S. application Ser. No. 12/772,861 filed May 3, 2010, now U.S. Pat. No. 7,868,044, which is a division of U.S. application Ser. No. 11/494,693, filed Jul. 28, 2006, now U.S. Pat. No. 7,737,181, which is a continuation-in-part of U.S. application Ser. No. 10/937,612, filed Sep. 10, 2004, now U.S. Pat. No. 7,579,377, which is a continuation of PCT/EP03/03246 filed Mar. 12, 2003 and designating the United States (published in English on Sep. 18, 2003 as WO 03/075908 A1), claiming benefit of U.S. Provisional Application No. 60/370,223, filed Apr. 8, 2002, and also claiming foreign priority under 35 U.S.C. §119 of Application No. 02/03070 filed in France on Mar. 12, 2002, each of the above applications being hereby expressly incorporated by reference in its entirety and each being assigned to the assignee hereof.

BACKGROUND OF THE INVENTION

Technical Field of the Invention

The present invention relates to novel pharmaceutical compositions comprising about 0.3% by weight of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid, the chemical structure of which is as follows:

in particular dermatological compositions, for the treatment of dermatological ailments, disorders, conditions or afflictions having an inflammatory or proliferative component.

Description of Background and/or Related and/or Prior Art

6-[3-(1-Adamantyl)-4-methoxyphenyl]-2-naphthoic acid (hereinafter referred to as adapalene) is a retinoid derived from naphthoic acid, having anti-inflammatory properties. This molecule has been the subject of development for the topical treatment of common acne and dermatoses sensitive to retinoids.

Adapalene is described in EP-0199636, and a process for synthesizing same is described in EP-0358574, both assigned to the assignee hereof.

The assignee hereof markets adapalene formulated at a weight concentration of 0.1% in the form of an alcoholic lotion, an aqueous gel and a cream. These compositions are suited for the treatment of acne.

SUMMARY OF THE INVENTION

Novel pharmaceutical compositions have now been developed containing adapalene at a weight concentration on the order of or about 0.3%, formulated into pharmaceutically acceptable media therefor, suited for the treatment (regime or regimen) of dermatological ailments, conditions or afflictions having an inflammatory or proliferative component. Specifically, it has now surprisingly been shown that, in addition to exhibiting better therapeutic efficacy compared to known compositions, the compositions according to the invention exhibit good tolerance, comparable to those of the known compositions with a lower concentration of active principle.

The results regarding tolerance observed in trials relating to photo-damaged skin (indication “photodamage”), obtained on individuals on average 65 years old, could not be exploited in the context of the present invention. Specifically, as regards use of adapalene on young individuals (in particular regarding acne with populations of teenagers or young adults), the skin exhibits very different physiopathological characteristics (presence of many lesions, in particular inflammatory lesions, modifying skin permeability, hypercornification of the follicular channel, immuno response, bacterial colonization of the skin (P. acnes), sebaceous hyperplasia with hyperseborrhea).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are graphs illustrating the effectiveness of the dermatological compositions of the present invention versus comparative compositions and controls.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION

Thus, the present invention features pharmaceutical compositions comprising about 0.3% by weight of adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid) relative to the total weight of the composition, or salts thereof, preferably in the form of aqueous gels. Such compositions are suited for the treatment (regime or regimen) of dermatological ailments, disorders or conditions having an inflammatory or proliferative component.

The term “adapalene salts” is intended to mean the salts formed with a pharmaceutically acceptable base, in particular organic bases such as sodium hydroxide, potassium hydroxide and aqueous ammonia, or organic bases such as lysine, arginine or N-methylglucamine.

The term “adapalene salts” is also intended to mean the salts formed with a pharmaceutically acceptable base, in particular in organic bases such as sodium hydroxide, potassium hydroxide and aqueous ammonia, or organic bases such as lysine, arginine or N-methylglucamine.

The term “adapalene salts” is also intended to mean the salts formed with fatty amines such as dioctylamine and stearylamine.

The pharmaceutical compositions according to the invention are preferably applied topically.

Topically, the pharmaceutical compositions according to the invention are more particularly suited for treatment of the skin and the mucous membranes, and may be in the form of ointments, creams, milks, pomades, powders, impregnated pads, solutions, gels, sprays, lotions or suspensions. They may also be in the form of suspensions of microspheres or nanospheres or of lipid or polymeric vesicles, or of polymeric patches and hydrogels for controlled release. These compositions for topical application may be in anhydrous form, in aqueous form or in the form of an emulsion.

In a preferred embodiment of the invention, the pharmaceutical compositions according to the invention are in the form of a gel, preferably aqueous, a cream, a lotion or a solution.

Accordingly, this invention also features pharmaceutical compositions comprising about 0.3% by weight of adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid) relative to the total weight of the composition, or salt thereof, formulated as creams.

This invention also features pharmaceutical compositions comprising about 0.3% by weight of adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid) relative to the total weight of the composition, or salt thereof, formulated as lotions.

By “lotion” is intended a fluid emulsion of water-in-oil or oil-in-water type. Preferably, the lotions according to the invention do not comprise any alcohol, but may comprise at least one glycol; consequently, they are not alcoholic, but preferably glycolic.

Another embodiment of the invention features pharmaceutical compositions comprising about 0.3% by weight of adapalene (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid) relative to the total weight of the composition, or salt thereof, formulated as solutions or spray solutions.

By “solution” is intended a liquid composition at ambient temperature (20-30°) and comprising a single phase. Such compositions are preferably alcoholic or may comprise at least one glycol or lipophilic component.

In particular, the pharmaceutical composition may be an aqueous gel comprising at least one ingredient selected from among:

-   -   Carbomers, for example Carbopol 980 NF marketed by NOVEON;     -   polymeric emulsifying agents such as PEMULEN (crosspolymers         acrylates/C10-30 alkyl acrylates, for example, PEMULEN TR1,         PEMULEN TR2, CARBOPOL 1342, CARBOPOL 1382, Carbopol 981 or         carbopol Ultrez marketed by the company NOVEON);     -   polysaccharidic biopolymers such as xanthan gum (for example,         Keltrol T and Xantural 180 marketed by the company Kelco);     -   gums such as caroub gum, guar gum;     -   alginates;     -   modified celluloses such as hydroxyethylcellulose,         methylcellulose, hydroxypropylcellulose (for example Natrosol         HHX 250 marketed by the company Aqualon),         hydroxypropylmethylcellulose and carboxymethylcellulose;     -   starch derived products such as Structure XL marketed by the         company National Starch;     -   a mix of polysorbate 80 and isohexadecane and acrylamide/sodium         acryloyldimethyltaurate (such as Simulgel 600); and     -   humectants or pro-penetrant agents such as propylene glycol or         equivalent, for example, glycerin and sorbitol, for example,         alkylene and polyalkylene glycols (C1 to CE) such as ethylene         glycol, polyethylene glycol (2 to 20 monomers), propylene         glycol, dipropylene glycol, butylene glycol, pentylene glycol,         hexylene glycol. These latter could be oxyethylened or not (2 to         50 QE). Glycol ethers are also representative such as         ethoxydiglycol, diethylene glycol monoethylether (tradename         transcutol HP by GATTEFOSSE company), dipelargonate propylene         glycol, propylene glycol laurate (tradename Lauroglycol by         GATTEFOSSE company), Propylene glycol dicaprate dicaprylate         (tradename Estol 1526 by UNIQEMA company); and     -   the pro-penetrants such as fatty esters family, fatty acids or         fatty alcohols or alcohols, for example, ethanol, dimethyl         isosorbide (tradename Arlasolve DMI by UNIQEMA company),         pyrrolidone methyl (tradename Pharmasolve by ISP company), oleic         acid (tradename Oleine V2 by Stearinerie Dubois company), PEG-8         capric/caprylic glycerides (tradename LAERASOL by GATTEFOSSE         company) and oleic alcohol (tradename HD EUTANOL V PH by COGNIS         company).

In particular, the pharmaceutical composition may be a cream comprising at least one ingredient selected from among:

-   -   mineral oils such as perhydrosqualene;     -   silicone oils such as cyclomethicone;     -   siliconed oily components such as siliconed fatty components;     -   non-siliconed fatty components such as vegetable, mineral,         animal or synthetic oils;     -   tensioactive agents or emulsifying agents, preferably such as         PEG-20 methyl glucose sequistearate or Methyl glucose         sesquistearate.

Among the non-siliconed oily components, the common oils are representative such as paraffin oil, Vaseline (or petroleum jelly), almond oil, perhydrosqualene, apricot oil, wheat germs oil, sweet almond oil, calophyllum oil, palm oil, castor oil, avocado oil, jojoba oil, olive oil or cerales germs oil; fatty acids esters or fatty alcohols esters such as dodecyl octyl octanoates, alcohols or polyalcohols decanoates or ricinoleates; fatty acids triglycerides; glycerides; hydrogenated polyisobutene, solid at 25° C. hydrogenated oils; lanolines; solid at 25° C. fatty esters; adipate diisopropyl (tradename Crodamol DA by Croda company), PPG 15 stearyl ether (tradename Arlamol E by UNIQEMA company), octyl dodecanol (tradename Eutanol G by COGNIS company), Caprilic/capric triglycerides (tradename Miglyol 812N by SPCI company), C12-C15 alkyl benzoate (tradename Tegosoft TN by Degussa company).

As tensioactive agents or as emulsifying agents, several components are representative selected from among PEG-20 methyl glucose sequistearate (tradename GLUCAMATE SSE 20 by Amerchol company) or Methyl glucose sesquistearate (tradename GLUCATE SS by Amerchol company), unsaturated or saturated fatty acids esters, oleic acid or isostearic acid such as polyglycerin and isostearic acid esters (tradename LAMEFORM TGI by SIDOBRE-SINNOVA HENKEL company), sorbitan isostearate (tradename ARLACEL 987 by UNIQEMA company), sorbitan sesquioleate (tradename ARLACEL 83 by UNIQEMA company), sorbitan laurate (tradename SPAN 20 by UNIQEMA company), glycol and isostearic acid esters such as PEG-6 isostearate (tradename OLEPAL ISOSTEARIQUE by GATTEFOSSE company), sorbitol and oleic acid esters such as polysorbates (tradename TWEEN by UNIQEMA company), fatty alcohols ethers such as oleic acid and particularly glycol and oleic acid esters such as oleths (tradename BRIJ by UNIQEMA company), oxyethylenated sorbitan monostearate, fatty alcohols such as stearylic alcohol or cetylic alcohol and particularly selected from among macrogol 21 stearylether (tradename BRIJ 721 by UNIQEMA company), macrogol 2 stearylether (tradename BRIJ 72P by UNIQEMA company), glyceryl/PEG 100 stearate (tradename Arlacel 165FL by UNIQEMA company), ceteareth 20 (tradename Eumulgin B2 by COGNIS company), PEG-6 and PEG 32 palmitostearate (tradename TEFOSE 1500 by GATTEFOSSE company).

In particular, the pharmaceutical composition may be a lotion comprising at least one ingredient selected from among:

-   -   humectant agent or pro-penetrant agent such as propylene glycol         (or equivalent such as glycerin and sorbitol), polyethylene         glycol, PEG400;     -   mineral oils such as perhydrosqualene as previously described;     -   lipophilic components such as Caprilic/capric triglycerides as         previously described;     -   emulsifying agents such as described, for example, PEG-20 methyl         glucose sequistearate and methyl glucose sequistearate.

Also in particular, the pharmaceutical composition may be a solution or a spray solution comprising alcohol and at least one ingredient selected from among:

-   -   humectant agent or pro-penetrant agent as described previously         and preferably such as propylene glycol, polyethylene glycol, or         PEG400;     -   a lipophilic component, such as siliconed or non-siliconed fatty         components or Caprilic/capric triglycerides.

Preferably in the form of gel, the composition has of following formula:

Adapalene 3 mg Carbomer 940 (Carbopol 980 NF) 11 mg Disodium edetate 1 mg Methyl paraben 2 mg Poloxamer 124 2 mg Propylene glycol 40 mg Sodium hydroxide: amount required to obtain a pH 5.0 +/− 0.3 Purified water q.s. 1 g

The pharmaceutical compositions according to the invention may also comprise inert additives or combinations thereof, such as:

wetting agents;

flavor enhancers;

preservatives such as para-hydroxybenzoic acid esters;

stabilizers;

moisture regulators;

pH regulators;

osmotic pressure modifiers;

emulsifiers; UV-A and UV-B screening agents; and

antioxidants, such as α-tocopherol, butylhydroxyanisole or butylhydroxytoluene, superoxide dismutase, ubiquinol or certain metal chelating agents.

Of course, those skilled in the art will take care to select the optional compound(s) to be added to these compositions in such a way that the advantageous properties intrinsically associated with the present invention are not, or are not substantially, adversely affected by the envisaged addition.

The pharmaceutical compositions according to the invention are suited for the treatment of dermatological ailments, conditions and afflictions having an inflammatory or proliferative component, selected from the group consisting of:

-   -   common acne, comedones, polymorphous acne, nodulocystic acne,         acne conglobata, secondary acne such as solar, drug-related or         occupational acne;     -   widespread and/or severe forms of psoriasis, ichtyoses and         ichtyosiform states;     -   Darier's disease;     -   actinic keratoses;     -   palmo plantar keratoderma and keratosis pilaris;     -   leucoplasias and leucoplasiform states, lichen planus;     -   any benign or malignant, severe and extensive dermatological         preparations.

The compositions according to the invention are particularly suitable for the treatment of acne, such as common acne, and in particular for the treatment of common acne of moderate to moderately severe intensity.

Various formulations of compositions comprising 0.3% of adapalene will now be given, it being understood that same are intended only as illustrative and in nowise limitative. Also given are results showing the therapeutic effects of the compositions according to the invention and the good tolerance to same by the treated patients.

In said examples to follow, all parts and percentages are given by weight, unless otherwise indicated.

Example 1—Formulation for Topical Administration

In this example, various specific topical formulations comprising 0.3% of adapalene are illustrated.

The adapalene of the present example was obtained from the company Sylachim.

(a) Cream:

Adapalene 3 mg Carbomer 934 (BF Goodrich Carbopol 974) 4.5 mg Disodium edetate 1 mg PEG 20 methyl glucose sesquistearate 35 mg Methyl glucose sesquistearate 35 mg Glycerol 30 mg Methyl paraben 2 mg Cyclomethicone 130 mg Perhydrosqualene 60 mg Phenoxyethanol 5 mg Propyl paraben 1 mg Sodium hydroxide quantity required for pH 6.5 +/− 0.3 Purified water q.s. 1 g

(b) Alcoholic solution:

Adapalene 3 mg PEG 400 700 mg Ethanol q.s. 1 g

(c) Lotion: (% w/w) Adapalene 0.30 Methyl paraben 0.15 Simulgel 600 PHA 1.00 Steareth 21 3.00 Glyceryl and PEG 100 stearate 3.00 Disodium edetate 0.10 Propyl paraben 0.05 Perhydrosqualene 5.00 Cetearyl isononanoate 5.00 Sodium Hydroxide 10% m/m q.s. pH 5.5 ± 0.5 Purified water q.s. 100

(d) Lotion: (% w/w) Disodium EDTA 0.1 Methyl paraben 0.2 Glycerine 7.0 Carbopol 981 NF 0.15 Propyl paraben 0.1 Ceteareth 20 3.0 Stearyl alcohol 2.0 Caprilic/capric triglycerides 7 Glyceryl and PEG 100 stearate 3.0 Cyclomethicone 5 6 Poloxamer 124 0.2 Propylene glycol 4.0 Adapalene 0.3 Simulgel 600 PHA 1.0 Solution aq. De NaOH 10% 0.4 Purified water q.s. 100

(e) Lotion: (% w/w) EDTA disodium 0.1 Methyl paraben 0.2 Carbopol 980 NF 0.15 Carbapol 981 NF 0.3 Glycerine 3.0 Phenoxyethanol 1.0 Propyl paraben 0.2 Methyl glucose sesquistearate 1.0 PEG 20 methyl glucose sesquistearate 5.0 Caprilic/capric triglycerides 6.0 Dimethicone 20 cst 1.0 Poloxamer 124 0.2 Propylene glycol 4 Adapalene 0.3 Sodium hydroxide 10% (w/w) 0.8 Purified water q.s. 100

(f) Aqueous Gel:

Adapalene 3 mg Carbomer 940 (Carbapol 980) 11 mg Disodium edetate 1 mg Methyl paraben 2 mg Poloxamer 124 2 mg Propylene glycol 40 mg Sodium hydroxide: amount required to obtain a pH 5.0 +/− 0.3 Purified water q.s. 1 g

(g) Aqueous Gel:

Adapalene 3 mg Xanthan gum 8 mg Hydroxypropylethyl cellulose 10 mg Disodium edetate 1 mg Methyl paraben 2 mg Phenoxyethanol 10 mg Poloxamer 124 2 mg Propylene glycol 40 mg Purified water q.s. 1 g

(h) Cream Gel:

Adapalene 3 mg Simulgel 600 PHA 20 mg Cetearyl isononanoate 100 mg Disodium edetate 1 mg Methyl paraben 2 mg Poloxamer 124 2 mg Propylene glycol 40 mg Purified water q.s. 1 g

(i) Cream gel:

Adapalene 3 mg Pemulen TR1 5 mg Mineral oil 120 mg Disodium edetate 1 mg Methyl paraben 2 mg Propyl paraben 1 mg Poloxamer 124 2 mg Propylene glycol 40 mg Sodium hydroxide: amount required to obtain a pH 5.0 +/− 0.3 Purified water q.s. 1 g

(j) Spray solution: (% w/w) Adapalene 0.3 Caprilic/capric triglycerides 50 N-methyl pyrrolidone 3 Ethanol q.s. 100

Example 2—Effectiveness of 0.3% Adapalene Gel and Comparison with 0.1% Adapalene Gel

Tests were carried out on a population consisting of patients suffering from acne. In this population, three groups were differentiated; the first received a daily topical application of the 0.3% adapalene gel, the second a daily topical application of the 0.1% adapalene gel in the same vehicle, and the third is a control group which receives a daily topical application of the gel corresponding to the composition of the first two gels but containing no active agent.

FIGS. 1 to 3 provide the results obtained in terms of regression of the number of lesions according to their nature.

These observations lead to the following conclusions:

the 0.3% adapalene gel acts more rapidly than the 0.1% adapalene gel; specifically, from the fourth week of treatment, a difference is noted between the effectiveness of the 0.1% adapalene gel and the 0.3% adapalene gel;

the 0.3% adapalene gel produces a clearly greater therapeutic effect after 8 weeks of treatment.

Example 3—Tolerance Regarding the 0.3% Adapalene Gel

1. Measurement of the Plasma Concentration of Adapalene:

Eight individuals suffering from common acne of medium to moderately severe intensity are treated for 10 days with 2 g of 0.3% adapalene gel applied daily over 1000 cm² of skin to be treated (face, chest and back).

Blood samples are taken on the days 1, 2, 4, 6, 8 and 10. During day 10, and following the final application, samples are taken at 1, 2, 6, 8, 10, 12, 16 and 24 hours.

The plasma concentration of total adapalene (free and conjugated) in these samples is determined using the following protocol:

enzymatic hydrolysis with a mixture of β-glucurodinase and arylsulfatase;

liquid-liquid extraction;

passage through HPLC (high performance liquid chromatography); and

then fluorometric detection.

This method makes it possible to detect a minimum concentration of 0.15 ng/ml and permits quantification of the adapalene for a minimum concentration of 0.25 ng/ml.

CONCLUSION

The plasma concentrations of adapalene measured after 10 days of treatment are very low and confirm the safety of daily use of the 0.3% adapalene gel.

2 a) Clinical Observation of the Side Effects Caused by Topical Administration of the 0.3% Adapalene Gel:

Two types of observation could be made:

firstly, monitoring of the patients treated within the framework of point 1 of the present example 3 made it possible to note that tolerance to the 0.3% adapalene gel was good for all patients. They all showed signs of dryness of the skin and of desquamation with a maximum on the seventh day of treatment, these symptoms then decrease up to the end of the treatment.

2 b) Furthermore, Reference May Also be Made to the Tests Described in Example 2 Above:

In parallel to the measurements of effectiveness, the experimenters recorded the possible side effects caused, firstly, by topical application of the 0.3% adapalene gel and those caused, secondly, by application of the 0.1% adapalene gel; finally, the same observations were made on a control population to which a gel without active principle was administered.

These observations are reported in the table below.

Local undesirable 0.3% adapalene 0.1% adapalene Vehicle gel effects gel (N = 70) gel (N = 70) (N = 74) Skin and secondary 31 (44.3%) 28 (40.0%) 5 (6.8%) structures (nails, hair) Dry skin 16 (22.9%) 13 (18.6%) 2 (2.7%) Erythema 8 (11.4%) 3 (4.3%) 0 (0.0%) Skin discomfort 8 (11.4%) 7 (10.0%) 0 (0.0%) Desquamation 6 (8.6%) 5 (7.1%) 0 (0.0%) Dermatitis 3 (4.3%) 1 (1.4%) 0 (0.0%) Pruritus 3 (4.3%) 1 1.4%) 1 (1.4%) Irritant dermatitis 2 (2.9%) 7 (10.0%) 0 (0.0%) Local allergic reactions 1 (1.4%) 0 (0.0%) 0 (0.0%) Pediculosis 1 (1.4%) 0 (0.0%) 0 (0.0%) Contact dermatitis 1 (1.4%) 0 (0.0%) 0 (0.0%) Insolation 1 (1.4%) 3 (4.3%) 1 (1.4%) Burning sensation 1 (1.4%) 0 (0.0%) 0 (0.0%) Urticaria 1 1.4%) 0 (0.0%) 0 (0.0%) Infection 1 (1.4%) 0 (0.0%) 0 (0.0%) Excoriation 0 (0.0%) 0 (0.0%) 1 (1.4%) Eczema 0 (0.0%) 0 (0.0%) 1 (1.4%) Oedema 0 (0.0%) 1. (1.4%) 0 (0.0%)

From this table, it is noted that the occurrence of undesirable side effects is statistically the same for the two gels with the different concentrations of active agent. The intensity of the undesirable side effects is average, which leads to the conclusion that the two gels are well-tolerated by the patients.

On the basis of these observations, it may be concluded that patients suffering from common acne can be treated with 0.3% adapalene gel, such an exposure to adapalene being described as weak or very weak under clinical conditions.

It therefore ensues from these various studies that a pharmaceutical composition containing 0.3% of adapalene exhibits a benefit/risk ratio which makes it particularly suitable for the treatment of dermatological maladies having an inflammatory or proliferative component, and in particular, common acne.

Each patent, patent application, publication and literature article/report cited or indicated herein is hereby expressly incorporated by reference.

While the invention has been described in terms of various specific and preferred embodiments, the skilled artisan will appreciate that various modifications, substitutions, omissions, and changes may be made without departing from the spirit thereof. Accordingly, it is intended that the scope of the present invention be limited solely by the scope of the following claims, including equivalents thereof. 

What is claimed is:
 1. A method for treating common acne, comedones, polymorphous acne, nodulocystic acne, acne conglobata, or secondary acne afflicting the skin of an individual in need of such treatment, comprising topically administering to said individual a topically applicable pharmaceutical aqueous gel composition consisting essentially of an anti-acne effective amount of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid (adapalene) of 0.3% by weight thereof, formulated into a topically applicable, pharmaceutically acceptable aqueous gel medium therefor, wherein said aqueous gel medium comprises at least one ingredient selected from the group consisting of carbomers, polymeric emulsifying agents, polysaccharidic biopolymers, gums, alginates, modified celluloses, starch derived products, a mix of polysorbate 80 and isohexadecane and acrylamide/sodium acryloyldimethyltaurate, and mixtures thereof. 